128215 - nsIScriptableInputStream can not handle embedded \0 characters.

Status: RESOLVED DUPLICATE of bug 170585

(Core :: XPCOM, defect)

Description

[Mark Hammond [:markh] [:mhammond]]

Came up on IRC.

nsIScriptableInputStream defines read as:

    string read(in unsigned long aCount); 

This does not handle embedded \0 characters.

The "correct" fix is probably to use a byte array, but this makes usage from 
javascript a pain for the common case, and would be a nightmare to fix all the 
old code.

Therefore I propose a new:
void readBinary(in unsigned long aCount, out PRUint32 outCount, [retval, array, 
size_is(outCount)] out PRUint8 data); 

Then anyone who cares about binary data can go through the pain of that extra 
param and array management.  (Of course, PyXPCOM handles all that magically, so 
would look like a normal read, but that isn't really relevant ;-)

I'm happy to make a patch is there is agreement.

Comment 1

[Mike Shaver (:shaver -- probably not reading bugmail closely)]

Can we use the new ACString stuff?  jag?

void read(in unsigned long aCount, [retval] out ACString buf);

Comment 2

[Bradley Baetz (:bbaetz)]

darin?

Comment 3

[Darin Fisher]

hmm... brendan said that an octet array would be best, but that it would also be
slow until JS2 comes along.  cc'ing nisheeth since he did the xpconnect work... 
i wonder how xpconnect treats embedded nulls.

Comment 4

[Nisheeth Ranjan]

speaking to jag about this...  he will update this bug soon...

Comment 5

[jag (Peter Annema)]

Sure, |ACString| should be fine, as long as the supplying end provides a ptr +
length. If only given a ptr, we'll do a \0 search.

Comment 6

[jag (Peter Annema)]

Shaver: why the retval fu though?

  ACString read(in unsigned long aCount);

should work just fine.

Comment 7

[Mike Shaver (:shaver -- probably not reading bugmail closely)]

That would be too clear!  Ahem.

The [retval] foo came from a string-with-size attempt that predated my ACString
suggestion in my mind, if not in the bug.  Thanks for the clue.

Comment 8

[Doug Turner (:dougt)]

Feel free to reassign or to move tm back with a working patch.  :-)

Comment 9

[Pete Collins (MDG)]

*** This bug has been marked as a duplicate of 170585 ***